91138081 has 4 divisors (see below), whose sum is σ = 91239472. Its totient is φ = 91036692.

The previous prime is 91138049. The next prime is 91138127. The reversal of 91138081 is 18083119.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 91138081 - 2⁵ = 91138049 is a prime.

It is a super-2 number, since 2×91138081² = 16612299616725122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91138001) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 49335 + ... + 51148.

It is an arithmetic number, because the mean of its divisors is an integer number (22809868).

Almost surely, 2^91138081 is an apocalyptic number.

It is an amenable number.

91138081 is a deficient number, since it is larger than the sum of its proper divisors (101391).

91138081 is a wasteful number, since it uses less digits than its factorization.

91138081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101390.

The product of its (nonzero) digits is 1728, while the sum is 31.

The square root of 91138081 is about 9546.6266817133. The cubic root of 91138081 is about 450.0215314800.

The spelling of 91138081 in words is "ninety-one million, one hundred thirty-eight thousand, eighty-one".